Explanation:
Initial mass of the isotope 90-Sr in baby= 1.00 μg
Formula used :

where,
= initial mass of isotope
N = mass of the parent isotope left after the time, (t)
= half life of the isotope = 28.1 years
= rate constant

a) Time taken by the sample, t = 18 years


0.6415 μg will remain after 18 years.
b) Time taken by the sample, t = 70 years


0.1779 μg will remain after 70 years.
Answer:
33/16 S
Explanation:
In beta decay, the atomic number of the daughter nucleus increases by one unit while the mass of the daughter nucleus remains the same as that of the parent nucleus.
Hence, if we know that a beta decay has occurred, then the parent nucleus must have the same mass as its daughter nucleus but have an atomic number that is less than that of the daughter nucleus by only one unit, hence the answer above.
The values of the coefficients would be 4, 5, 4, and 6 respectively.
<h3>Balancing chemical equations</h3>
The equation of the reaction can be represented by the following chemical equation:
ammonia (g) + oxygen (g) ---> nitrogen monoxide (g) + water (g)
+
--->
+ 
Thus, the coefficient of ammonia will be 4, that of oxygen will be 5, that of nitrogen monoxide will be 4, and that of water will be 6.
More on balancing chemical equations can be found here: brainly.com/question/15052184
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Answer:
5.9 × 10^-6.
Explanation:
In the arrangements of crystal solids there is likely going to be an imperfection or defect and one of the defect or imperfections in the arrangements of solids is known as the Schottky defects. The Schottky defects is a kind of lattice arrangements imperfection that occurs when positively charged ions and negatively charged ions leave their position.
So, let us delve right into the solution of the question. We will be making use of the formula below;
Wb/ W = e^ - c/ 2kT.
Where Wb/ W= fraction of lattice sites, c= energy for defect formation = 1.86 eV, and T = temperature= 623° C= 896 k.
So, Wb/ W = e ^ -1.86/ (2 × 896 × 8.62 × 10^ -5).
Wb/ W= 0.000005896557435956372.
Wb/ W=5.9 × 10^-6.